254 CEYLON PEARL OYSTER REPORT. 



Fifth pair of natatory legs each 2-branched ; each branch composed of one bifid 

 joint, the outer branches each having 3 small spines on outer edge. A few 

 females were found in Galle Harbour and also off' Karativo Island in the Gulf of 

 Manaar. 



The abdomen and 5th natatory legs distinguish this from any other described form. 

 We have peculiar pleasure in naming it after Professor Herdman. 



Acartia clausi, Giesbr. 



A common British species. Occurred at the first 4 stations as far as the Gulf of 

 Suez, and once off Ceylon at the south end of the Cheval Paar. 



Acartia longiremis, Lillj. 

 Taken at 9 stations, from the English Channel to the Mediterranean off Messina. 



Acartia dubia, T. Scott. 

 Found in the Suez Canal and in the Red Sea. 



Acartia erythraa, Giesbr. 



Well distributed throughout the traverse, occurring at 53 stations, from the Gulf 

 of Suez, throughout the Indian Ocean, and around Ceylon. 



Acartia centrura, Giesbr, 



Occurred in Gulf of Suez and the Red Sea, and at G stations round Ceylon. 

 Previously reported from the Red Sea and Atlantic Ocean. 



Acartia negligens, Dana. 



Obtained at 38 stations, from Gulf of Suez onwards through the Indian Ocean, and 

 common around Ceylon. 



Tortanus gracilis (Brady). 

 One record only from about the Gulf of Suez. Brady records the species from the 

 Philippine Islands. 



Tortanus forcipatus (Giesbr.). 



Occurred at 3 Ceylon stations only, Adz., off Kalpentyn Island, Cheval and Periva 

 paars, and off Pantura, south of Colombo. Giesbrecht's specimens were from Amov, 

 China. 



Family : CYCLOPIPJE. 

 Thorellia brunnea, Boeck. 

 Found in washings from sponges, Gulf of Manaar, 



